Collaborative Research: Measurement of Copper Speciation in Basaltic Glasses using X-ray Absorption Spectroscopy, a New Window on Metal Solubility and Transport in Magmatic Systems

合作研究：使用 X 射线吸收光谱测量玄武岩玻璃中的铜形态，这是岩浆系统中金属溶解度和传输的新窗口

• 批准号: 1834941
• 负责人: Molly McCanta
• 金额: $ 9.89万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1834941&HistoricalAwards=false
• 关键词: Collaborative; Research; Measurement; Copper; Speciation

The solubility of metals such as copper (Cu) in silicate melts can be strongly influenced by natural properties of the magma such as pressure, temperature, and melt composition. Understanding how such things control metal solubility, particularly for Cu, is important for a number of reasons. It helps researchers understand potential driving mechanisms for core formation in terrestrial planets, or the conditions that lead to the formation of economically important metallogenic ore deposits. It's also key to understanding how volcanic degassing may impact metal emissions to the atmosphere. This study proposes to use synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy of natural and synthetic magmatic glasses with the goal of providing the first direct, experimental constraints on the speciation of Cu in terrestrial melts. XAFS is currently the only methodology available for directly measuring Cu speciation in magmatic glasses at natural concentrations with high spatial resolution. In addition to the scientific goal of constraining which Cu species exist in melts, this work will broaden the participation of minority students in geoscience, and train students in state-of-the-art experimental and analytical techniques.This will be achieved through three overlapping projects. Project 1 will include copper speciation measurements of synthetic basaltic glasses that are produced at controlled sulfur and oxygen conditions. This suite of synthetic glasses will have both oxygen and sulfur fugacity carefully controlled and will then be analyzed for changes in Cu speciation using XAFS. Project 2 includes Cu speciation measurements of natural glasses sampled from volcanic systems. This project targets natural samples from a sulfide-dominated system with H2O-poor melts (using samples collected from the Kilauea summit vent between 2008 and present), samples from a sulfide-dominated system with higher-H2O melts (from a basaltic cinder cone in the southern Cascade Range), and from sulfate dominated volcanics from both the southern Cascades Range and the Colima Graben in western Mexico. Project 3 will focus on developing advanced, synchrotron-based spectroscopic techniques for Cu K-edge XAFS of magmatic glasses, which will be applied to samples available from Projects 1 and 2, with a focus on developing High Energy-Resolution Fluorescence Detected XAFS (HERFD-XAFS) techniques for the analysis of Cu in geologic materials and magmatic glasses specifically. Such new HERFD-XAFS techniques hold the promise of providing superior spectroscopic sensitivity and resolution compared to conventional XAFS methods for uniquely constraining the copper ligands are present in these samples. These proposed measurements will be the first application of these methods to magmatic glasses and will establish a new database of spectroscopic measurements that will be available to the petrology community. Together, this suite of studies will significantly contribute to our understanding of metal solubility and transport in magmatic systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

铜 (Cu) 等金属在硅酸盐熔体中的溶解度会受到岩浆自然特性（如压力、温度和熔体成分）的强烈影响。出于多种原因，了解这些因素如何控制金属溶解度（尤其是铜）非常重要。它有助于研究人员了解类地行星核心形成的潜在驱动机制，或导致具有经济重要性的成矿矿床形成的条件。这也是了解火山脱气如何影响向大气中的金属排放的关键。本研究建议使用基于同步加速器的 X 射线吸收精细结构 (XAFS) 光谱来分析天然和合成岩浆玻璃，目的是对陆地熔体中铜的形态提供第一个直接的实验限制。 XAFS 是目前唯一可用于以高空间分辨率直接测量自然浓度岩浆玻璃中铜形态的方法。除了限制熔体中存在哪些铜形态的科学目标外，这项工作还将扩大少数民族学生对地球科学的参与，并培训学生最先进的实验和分析技术。这将通过三个重叠的项目来实现项目。项目 1 将包括在受控硫和氧条件下生产的合成玄武岩玻璃的铜形态测量。这套合成玻璃将严格控制氧和硫的逸度，然后使用 XAFS 分析铜形态的变化。项目 2 包括对从火山系统采样的天然玻璃进行铜形态测量。该项目的目标是来自以硫化物为主、熔体含量较低的系统的天然样品（使用 2008 年至今从基拉韦厄山顶喷口收集的样品）、以硫化物为主、熔体含量较高的系统的样品（来自位于喀斯喀特山脉南部），以及来自喀斯喀特山脉南部和墨西哥西部科利马地堑的硫酸盐为主的火山。项目 3 将重点开发先进的、基于同步加速器的光谱技术，用于岩浆玻璃的 Cu K 边缘 XAFS，该技术将应用于项目 1 和 2 提供的样品，重点是开发高能量分辨率荧光检测 XAFS (HERFD) -XAFS）技术，专门用于分析地质材料和岩浆玻璃中的铜。与传统的 XAFS 方法相比，这种新的 HERFD-XAFS 技术有望提供卓越的光谱灵敏度和分辨率，以独特地限制这些样品中存在的铜配体。这些提出的测量将是这些方法在岩浆玻璃上的首次应用，并将建立一个可供岩石学界使用的新的光谱测量数据库。总之，这套研究将极大地促进我们对岩浆系统中金属溶解度和迁移的理解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Direct Measurements of Copper Speciation in Basaltic Glasses Using X-Ray Absorption Spectroscopy: Understanding the Role of Sulfur in Copper Complexation in Melts

使用 X 射线吸收光谱直接测量玄武岩玻璃中的铜形态：了解硫在熔体中铜络合中的作用

• 发表时间: 2019-03
• 期刊: Lunar and planetary science conference abstracts
• 作者: 3) Lanzirotti, A.;Lee, L.;Head, E.;Sutton, S.R.;Newville, M.;McCanta, M.;Lerner, A.;Wallace, P.
• 通讯作者: Wallace, P.

The Impact of Vapor Bubbles and Sulfide Precipitates on Copper Complexing in Melt Inclusions

蒸气泡和硫化物沉淀对熔体夹杂物中铜络合的影响

• 发表时间: 2022-12
• 期刊: Transactions American Geophysical Union
• 作者: 2) Head, E.;Lanzirotti, A.;Wallace, P. J.;McCanta, M. C.
• 通讯作者: McCanta, M. C.

Direct measurements of copper speciation in basaltic glasses: understanding the relative roles of sulfur and oxygen in copper complexation in melts

直接测量玄武岩玻璃中的铜形态：了解熔体中铜络合中硫和氧的相对作用

• DOI: 10.1016/j.gca.2019.09.029
• 发表时间: 2019-12
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Lanzirotti, Antonio;Lee, Lopaka;Head, Elisabet;Sutton, Stephen R.;Newville, Matthew;McCanta, Molly;Lerner, Allan H.;Wallace, Paul J.
• 通讯作者: Wallace, Paul J.